Binomial Theorem

Please help

a)By writing down and solving a suitable equation in k, find a positive integer k such that

(x^20)^20-k(1/x)^k = x

where x is a variable.

Use the Binomial theorem and your answer in part a) to determine the coefficient of x in the expansion of

(2x^2-1/x)^20

Quote:

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Originally Posted by fair_lady0072002

Please help

a)By writing down and solving a suitable equation in k, find a positive integer k such that

(x^20)^20-k(1/x)^k = x

where x is a variable.

Use the Binomial theorem and your answer in part a) to determine the coefficient of x in the expansion of

(2x^2-1/x)^20

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Is there a typo here? The first and second questions seem to have nothing to do with each other.

Also, I believe there is no solution to a). The first term on the LHS is x^400 which would need to be cancelled by something in the second term. There is nothing in the second term to do this that would leave a linear term in x.

-Dan